Leap Year Checker
Check whether a year is a leap year, see why, and list leap years in a range.
About the Leap Year Checker
Enter a year to see whether it's a leap year, which rule decides it and the next leap year. Add an end year to list every leap year in between.
The Gregorian calendar adds a leap day to keep in step with the solar year of about 365.2422 days. Every year divisible by 4 is a leap year, except century years, which are leap years only if divisible by 400.
The formula
Leap if (divisible by 4 and not by 100) or divisible by 400
Worked example
2028: divisible by 4, not by 100, so a leap year
- 2100: divisible by 100 but not by 400, so not a leap year
- 2000: divisible by 400, so it was a leap year
- Leap years 2028–2060: every fourth year, nine in all
Questions people ask
Why skip century years?
Adding a day every 4 years overshoots by about 3 days every 400 years; dropping 3 century leap days fixes that.
When is the next skipped leap year?
2100.
How many days in a leap year?
366, with 29 days in February.